1. Field of the Invention
The present invention is generally directed to a process for preparing a shingle material. More particularly, the present invention relates to a process for preparing cellular polyvinyl chloride materials for use as shingles to mimic traditional, Western red cedar shingles.
2. Background of the Invention
Traditionally, side and roof shingles are made from Western red cedar or Eastern white cedar. In recent years, fiber cement and a variety of polymers have been pressed and/or injection molded to simulate the look of these wood standards. Each of these materials, however, has certain inherent problems that make them less than ideal from a building perspective.
For example, shingles made from cedar tends to absorb moisture, and to, consequently, warp, decay, and rot. Additionally, insects are attracted to the wood, and, therefore, contribute to the decay. Furthermore, when painted, the paint tends to blister, peel, and crack.
Although it absorbs less water than wood siding materials, fiber cement shingles do absorb some moisture if not carefully installed and maintained. To reduce the moisture and paint problems, the cut edges of the fiber cement shingles must be carefully treated. Furthermore, fiber cement shingles are flat (not beveled), unduly heavy, brittle, require specialized tools and instruments for installation, and debris formed during its installation may create health risks. For these reasons, then, fiber cement shingles are difficult to install and maintain, and because they are flat and uniform in appearance, they are not a close aesthetic match to wood shingles.
Molded polymer shingles and shingle panels improve upon the use of wood and fiber cement in that they are less subject to water related maintenance issues. However, molded shingles are very light and hollow giving them a less authentic appearance and feel. Additionally, molded shingles and panels must be overlapped to accommodate expansion and contraction. As a result, a tell-tale sign of molded polymer versus cedar and fiber cement shingles is the overlapping joints and repeating patterns that appear on most molded polymer installations. Also, molded shingles must be inserted into j-channel trim installed around windows, doors and at all corners in order to accommodate expansion and contraction of the polymer with changes in temperature. Further, molded polymer shingles and shingle panels have tended to discolor over time; thereby diminishing their perceived value considerably.